The present invention is directed to the field of wireless communications. In particular, the present invention is directed to the field of wireless communications in a local area, such as a home or office.
The Industrial, Scientific and Medical (ISM) frequency spectrum is a part of the electromagnetic spectrum that has traditionally been reserved for industrial, scientific or medical applications. Three of the bands within the ISM spectrum are the A band, 902-928 MHz; the B band, 2.4-2.484 GHz; and the C band, 5.725-5.875 GHz. In 1995, the Federal Communication Commission (FCC) expanded the applications for the ISM band to permit the use of low-power transceivers. Today, many in-home wireless communications devices operate in this band, including wireless LANs, cordless telephones, cable-less headphones, door-chimes, garage door openers, TV/VCR/stereo remote control units, baby-phones, etc. Moreover, outdoor devices such as car alarms and automatic door locks operate in this spectrum. The FCC has established that no one may enjoy an exclusive right to any portion of the ISM spectrum. Thus, systems using this spectrum are subject to interference by other systems, potentially degrading the performance of these systems. Techniques for multiple access in the ISM spectrum exist, including direct sequence spread spectrum and frequency hopping spread spectrum techniques. In many applications, however, such techniques are too expensive or otherwise infeasible for use in a local area such as a home or office.
Despite the potential for mutual interference, wireless systems for the home and office environment that use the ISM spectrum continue to be developed and marketed. Because they operate in the ISM spectrum, the systems are generally insensitive to or can sustain some level of mutual interference. However, because of the potential for mutual interference, transmission power is often lowered, thereby reducing the coverage area. Thus, in such systems, one of the critical issues is the coverage area inside and around the home or office.
In achieving coverage of a local area, the number, power and positioning of the transceivers/antennas must be considered. Tradeoffs must often be made between coverage and cost. For example, as the radiating power of a transceiver is reduced, the lower its cost but also the less its coverage. The positioning of the transceiver or antenna within a home or office thus becomes critically important. Moreover, the task of positioning the transceivers or antennas can itself be costly and time-consuming.
Typically, an empirical trial-and-error process ensues, in which the transceivers or antennas are repeatedly positioned and coverage tested until adequate coverage is achieved. Alternatively, a large number of transceivers or antennas are positioned in a local area to guarantee adequate coverage. A third option is simply to install a high-power transceiver, i.e., 100 mW or more, to achieve adequate coverage. Such high-power transceivers, however, are typically too large and expensive for use in a home or office. They also tend to compound the mutual interference problem.
Similarly, it is difficult to achieve adequate coverage in a home or office using low power transceivers. The desired coverage area often includes multiple rooms separated by interior walls. Interior walls force either an increase in transceiver power requirements or an increase in the number of transceivers, the latter to achieve line-of-sight coverage. Transceiver or antenna positioning may be customized for each home or office, but customization only increases the cost. In sum, current wireless solutions are either prohibitively expensive, subject to mutual interference, or achieve inadequate coverage.
Recently, technology has been announced in which data transmission can occur over AC power lines in a home or office. See www.interlogis.com. However, this is still a wired technology, and hence is subject to the mobility limitations, coverage restrictions, and cabling requirements of wired systems.
Hence, there is a need for a system and method for achieving wireless communications coverage in a local area which achieves adequate coverage, is not prohibitively expensive, and which otherwise overcomes the disadvantages of the prior art.
In accordance with the purpose of the invention as broadly described herein, there is provided an electrical apparatus configured in various embodiments to include an antenna, a transceiver, or a repeater. In one embodiment, the apparatus comprises: a power distribution system for distributing power to the apparatus and for carrying a first signal relating to a second signal, the second signal for receiving or transmitting over a wireless interface; and an antenna coupled to the power distribution system for receiving or transmitting the second signal over a wireless interface.
In a second embodiment, the apparatus comprises a power distribution system for distributing power to the apparatus; and a transceiver coupled to the power distribution system for receiving or transmitting over a wireless interface a first signal relating to a second signal, the second signal for carrying over the power distribution system.
In a third embodiment, the apparatus comprises a power distribution system for distributing power to the apparatus; and a repeater for repeating a signal received over a wireless interface.
A fourth embodiment comprises a wireless communication system including a plurality of nodes configured to communicate with one another over a wireless interface, wherein at least one of the nodes comprises the apparatus of the foregoing first embodiment coupled to a user device through a power distribution system. The power distribution system is configured to carry the first signal which relates to the second signal, the second signal for transmitting or receiving over the wireless interface.
A fifth embodiment comprises a wireless communication system including a plurality of nodes configured to communicate with one another over a wireless interface, wherein at least one of the nodes comprises the apparatus of the foregoing second embodiment coupled to a user device through a power distribution system. The power distribution system is configured to carry the second signal from which is derived the first signal as transmitted over the wireless interface, or which is derived from the first signal as received over the wireless interface.
A method of operation of an electrical apparatus configured in accordance with the subject invention comprises: receiving a first signal over a wireless interface; and transmitting a second signal derived from the first signal to a user over the power distribution system of the apparatus.
A second such method comprises: providing a first signal over the power distribution system of the apparatus; and transmitting a second signal derived from the first over a wireless interface.
A third such method comprises: receiving a signal over a wireless interface; demodulating the signal to baseband frequencies; and providing the demodulated signal to a user over a power distribution system.
A fourth such method comprises: receiving a signal at baseband frequencies from a user; providing the signal to a modulator over a power distribution system; modulating the signal to a desired carrier frequency; and transmitting the modulated signal over a wireless interface.
In any and each of the foregoing embodiments, the first signal may be the second signal, or it may be different from the second signal.